1. Field of the Invention
The present invention relates to compressors, and more particularly, to a compressor having an improved structure that enables easy mounting of a suction muffler, and a discharge muffler, on a head assembly of a compression cylinder.
2. Background of the Related Art
The compressor boosts a pressure of a working fluid by receiving a power from an electric motor or a turbine, and applying a compressive work to air, refrigerant, or other special gas. The compressor is widely used starting from home appliances, to plant industries in the fields of air conditioners, or refrigerators.
Depending on methods of compression, there are positive displacement compressors, and dynamic compressors, or turbo compressors. The positive displacement compressors boost a pressure by reduction of a volume, and have reciprocating compressors, and rotary compressors.
The reciprocating compressor, compressing the working fluid by means of a piston reciprocating inside of a cylinder, is advantageous in that a high compression efficiency can be provided by using comparatively simple mechanical components.
The rotary compressor, compressing the working fluid by means of a roller revolved inside of a cylinder with an eccentricity, can provide a high compression efficiency at a speed lower than the reciprocating compressor.
FIG. 1 illustrates a typical example of the reciprocating compressor, referring to which the reciprocating compressor will be described in more detail.
Referring to FIG. 1, two pieces of cases 1 assembled together form an enclosed space, in which a frame 2 is provided. The frame 2 is supported on the cases 1 with springs 4.
There is a crank shaft 6 mounted passed through a central part of the frame 2. For this, there is a boss 3 in the central part of the frame 2 for stable support of the crank shaft 6.
The crank shaft 6 mounted thus, is rotated by the motor 5, which is provided with a stator 5a and a rotor 5b. The stator 5a is fixed to the frame 2, and the rotor 5b is fixed to the crank shaft 6. Since the rotor 5b positions inside of the stator 5a, the crank shaft 6 rotates together with the rotor 5b when power is provided to the motor 5.
Referring to FIG. 1, there is an eccentric pin 6a on top of the crank shaft 6 at an eccentric position from a rotation center of the crank shaft 6. There is a balance weight 6b on top of the crank shaft at an opposite side of the eccentric pin 6a. The balance weight 6b prevents the crank shaft 6 from shaking due to weight of the eccentric pin 6a during rotation of the crank shaft 6.
In the meantime, there is lubricating oil held on a bottom of the case 1, and the crank shaft 6 has oil passages 6c inside of the crank shaft 6. Accordingly, when the crank shaft 6 rotates, lubricating oil moves following the oil passage 6c, and sprayed from the top of the crank shaft 6. According to this, the lubricating oil is supplied to all mechanically operative components in the case 1.
There are a cylinder 10 having a compression chamber 11 therein in one side part of top of the frame 2, and a piston 15 in the compression chamber 11 having one end coupled to the eccentric pin 6a. Therefore, when the crank shaft 6 rotates, the piston 15 reciprocates within the compression chamber 11.
There is a valve assembly 20 mounted on an end of the cylinder 10 for controlling flow of a working fluid, for an example, refrigerant introduced into the compression chamber 11, compressed therein, and discharged therefrom, and there is a head assembly 30 on top of the valve assembly 20 for guiding flow of the working fluid.
In the meantime, referring to FIGS. 2 and 3, structures of the valve assembly 20 and the head assembly 30 can be understood more easily. Therefore, the valve assembly 20 and the head assembly 30 will be described in more detail with reference to the drawings. Examples illustrated in FIGS. 2 and 3 have slightly different structures.
The valve assembly 20 is provided with a suction valve 21, a valve plate 22, a discharge valve 23, and a gasket 24 (see FIG. 3). The valve plate 22 has a suction port 22a for drawing the working fluid, i.e., the refrigerant, into the compression chamber 11 of the cylinder 10, and a discharge port 22b for discharging the refrigerant to an outside of the compression chamber 11.
The suction valve 21 is between the valve plate 22 and the cylinder 10, and operative by an elastic force and a pressure difference for opening/closing the suction port 22a. The discharge valve 23 is opposite to the suction valve 21 to face the valve plate 22 for opening/closing the discharge port 22b by a pressure difference and an elastic force. The gasket 24 is provided between the discharge valve 23 and the head assembly 30 for preventing leakage of the refrigerant.
The head assembly 30 is provided with a head plate 31 adjacent to the gasket 24, a head cover 32 attached to the head plate 31, and a suction muffler 33 and a discharge muffler 34 (not shown in FIG. 2). In the meantime, the head assemblies illustrated in FIGS. 2 and 3 have different structures, which will be described.
Referring to FIG. 2, the head plate 31 and the head cover 32 forms a discharge chamber 32a for discharging working fluid, i.e. the refrigerant compressed in the compression chamber 11. Both the head plate 31 and the heat cover 32 have fastening holes 25 for bolts 7. The valve assembly 20 and the cylinder 10 also have the fastening holes 25. Therefore, the head assembly 30 and the valve assembly 20 are fastened to the cylinder 10 with the bolts 7, rigidly.
Both the head plate 31 and the head cover 32 have cut away portions 35 respectively, to expose the suction port 22a of the valve assembly 20 as shown in FIG. 2. The suction port 22a has a discharge part 33a of the suction muffler 33 connected thereto. For this, the discharge part 33a is inserted in the cut away part 35, and a clamp 36 is fastened to cover the discharge part 33a. The clamp 36 is fastened with the bolts 7 passed through the fastening holes 25 on both sides of the discharge part 33a, to fasten the suction muffler 33, rigidly.
In the meantime, in the head assembly 30 shown in FIG. 3, the head plate 31 has the suction muffler 33 fixed thereto, and the suction muffler 33 has a suction pipe 33b connected thereto (see FIG. 4). The head plate 31 had the head cover 32 brazed thereto.
Referring to FIG. 4, there is a suction guide 32b between the head plate 31 and the head cover 32, for guiding the refrigerant from the suction muffler 33 to the compression chamber 11. As shown in FIG. 4, the discharge chamber 32a between the head plate 31 and the head cover 32 is filled with the refrigerant discharged from the compression chamber 11.
Referring to FIGS. 3 and 4, the head plate 31 has the discharge muffler 34, which is in communication with the discharge chamber 32a, connected thereto. There is a damping pipe 37 that makes the discharge chamber 32a and the discharge muffler 34 in communication, and has a form wound many times in a circular form. There is a discharge pipe 34a connected to the discharge muffler 34. Therefore, the refrigerant filled in the discharge chamber 32a is introduced into the discharge muffler 33 through the damping pipe 37, and discharged to the discharge pipe 37.
The operation of the compressor will be described.
When power is provided to the motor 5, the crank shaft 6 rotates together with the rotor 5b, and the piston 15 connected to the eccentric pin 6a reciprocates within the cylinder 10. In the meantime, the suction muffler 33 is filled with refrigerant through the suction pipe 33b. 
If the piston 15 moves to increase a volume of the compression chamber 11, with consequential decrease of a pressure of the compression chamber 11, the suction valve 21 is opened, such that the compression chamber 11 draws in the refrigerant from the suction muffler 33 through the suction guide 32b. 
If the piston 15 reverses to decrease a volume of the compression chamber 11, with consequential increase of the pressure of the compression chamber 11 as the refrigerant is compressed. When the pressure of the compression chamber 11 rises over a certain pressure, the discharge valve 23 is opened, such that high pressure refrigerant fills the discharge chamber 32a, and therefrom flows to the discharge pipe 33b through the discharge muffler 33.
However, the related art compressor has the following problems.
First, in the case of the head assembly 30 shown in FIG. 2, the use of the clamp 36 for mounting the suction muffler 33 increases a number of components. The handling of the bolts and tool in a state the clamp 36 and the suction muffler 33 are held in position for fastening the clamp 36 to the head cover 32 leads assembly cumbersome, and deformation of the clamp 36, resulting in a poor accuracy of assembly, causes leakage of the refrigerant.
Next, in a case of head assembly 30 shown in FIGS. 3--5, the head plate 31, the head cover 32, the suction muffler 33, and the discharge muffler 34 are assembled with brazing, which causes defects because holding the damping pipe in position during the brazing is difficult, causing imperfect communication between the damping pipe 37 and the discharge chamber 32a, to introduce a portion of the refrigerant from the discharge chamber 32a to the discharge muffler 34, directly. According to this, pulsation and noise of the refrigerant can not be eliminated from the compression chamber 11 properly, to cause emission of loud noise from the compressor, with drop of a performance of the compressor.